Injection molded rivet-style fastener and housing with snap assembly functionality along with an injection molding process for producing such a rivet without an undercut feature

ABSTRACT

The present invention discloses a fastener assembly having an engaging portion with a projecting stem which is interiorly hollowed over at least an intermediate extending range. The stem includes a solid end most extending portion. A receiving portion is provided with an inner rim defined edge, a diameter of an aperture between the rim edge being less than a diameter of an inserting portion of the stem. Upon forcible passage of the solid end of the fastener past the narrowed rim edge, an intermediate hollowed interior portion of the stem aligning with the narrowed rim edge and exhibiting a controlled collapse against said rim edge in order to anchor the portions together.

BACKGROUND OF THE INVENTION CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the priority of U.S. Ser. No. 62/322,645 filed Apr. 14, 2016, the contents of which is incorporated herein in its entirety.

FIELD OF THE INVENTION

The present invention discloses a no snap-action rivet and associated non-slide actuated molding process avoiding the necessity of forming an undercut profile in the molded rivet stem and allowing the formation of a partially hollowed rivet stem (solid at the outermost end but hollowed from the intermediate interior through the central opening at the flattened top). A receiving location is provided with an opposing and through-seating aperture, the latter typically including an angled or saucer-like or chamfered profile which terminates in a thin/sharpened inner rim edge which defines a diameter of somewhat lesser dimension than that presented by the cross section of the inserting rivet stem.

In this fashion, and upon press-fitting the solid end-most portion (tip) of the rivet stem through the aperture in resistive contact with the narrowed rim edge, the intermediate extending walls of the stem defined by the hollow interior which align with the narrowed rim edge are caused to deflect or bow inwardly to thereby create the equivalent of a desirable (and withdrawal resistant) undercut

BACKGROUND OF THE RELEVANT ART

The prior art discloses a variety of combination compression/expansion fasteners assemblies. A first example of this is depicted in FR1255864 (ITW) which teaches a deformable rivet assembly with an arcuate and bulbous end configuration along its stem which deflects from a collapsed (concave) position to protruding (convex) position.

The tubular rivet of Nichiei Bussan Co., Ltd. (FR 2 302 442) exhibits a linearly collapsible outer tubular wall (see FIGS. 4A-4B) which is actuated by a retractable (upwardly displacing) inner stem (also called a male element) 3. The blind rivet of EP 1 217 229 exhibits an inserting body 2 with irregular radial serrations 12, 14, 16 and which, upon being compressed within a mounting hole by a mandrel 6, converts (i.e. linearly compresses and radially expands) from the position of FIG. 2d to that in FIG. 2e . Also noted is the wall fastener of Schaap, U.S. Pat. No. 4,834,601, the splined fastener of Tyson US 2014/0133937, and the non-compressing stems in the fasteners of JP 855099 and W2007285330.

SUMMARY OF THE PRESENT INVENTION

The present invention discloses a fastener assembly having an engaging portion with a projecting stem which is interiorly hollowed over at least an intermediate extending range. The stem includes a solid end most extending portion in communication with at least an intermediate hollowed out interior cavity. A receiving portion is provided with a surface having an inner rim defined edge, a diameter of an aperture between the rim edge being less than a diameter of an inserting portion of the stun. Upon forcible passage of the solid end of the fastener past the narrowed rim edge, the intermediate hollowed interior portion of the stem aligns with the narrowed rim edge and is caused to collapse against the rim edge in order to anchor the portions together.

Additional features include the stem having any of a circular or other polygonal exterior cross sectional profile. The inner rim defined edge may further exhibit a chamfered shape terminating in a narrowed rim profile. The inner rim edge defines a flat profile equal in dimension to that of the lower engaging portion.

In an additional variant, the exterior cross sectional profile of the stem and the inner rim define edge can define either matching or varying profiles. The engaging and receiving locations can also exhibit any dimensional shape, and it is also envisioned that these can assemble according to any open or enclosing three dimensional housing.

An associated forming process is also disclosed for injection molding the rivet and dispenses with the need of providing for movable slide actuation of the undercut forming portions (e.g. providing a no-action mold) and in order to create the fastener of the present invention. Other applications of the article and associated forming process include replacing sonic welds, push pins or traditional latching features. Post and hole configurations of any article produced according to the present inventions can vary from circular as shown, it further being understood that the post and hole can additionally vary from one another in use.

BRIEF DESCRIPTION OF TITLE DRAWINGS

Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which:

FIG. 1 and related FIG. 5B is an illustration in cutaway of a selected no-action snap rivet feature according to one non-limiting embodiment of the present inventions;

FIGS. 2A-2C present a series of views of an undercut snap action fastener according to the Prior Art;

FIGS. 3A-3C present a series of process views of a mold assembly with movable slides for producing the snap action fastener according to the Prior Art;

FIG. 4 is an exploded view of no-action snap fastener according to a further embodiment;

FIGS. 5A-5B are cutaway exploded and assembled views, respectively, of the no-action snap fastener of FIG. 4;

FIGS. 6A-6B correspond to FIGS. 3A-3C and illustrate a process view of a mold assembly not requiring movable slides for producing the fastener of FIG. 4:

FIGS. 7, 8 and 9A-9B illustrate a collection of alternate applications of the no-action snap fastener and which can be utilized to replace such as sonic welds, push pins or traditional latching features;

FIG. 10 is an assembled cutaway in perspective of a variant of the no-action snap fastener utilizing a non-chamfered configuration in the mounting surface hole in combination with a more elongated and interiorly hollowed stem than in the variant of FIG. 1;

FIGS. 11A-11B illustrated another embodiment related to that of FIG. 1 and illustrating a polygonal (non-circular cross sectional shaped) configuration associated with the underside projecting stem of the fastener as well as a mating inner narrowed perimeter edge configuration associated with the chamfer configured aperture in the base mounting layer; and

FIGS. 12-14 are a further collection of exploded views of alternate no-action snap fasteners exhibiting varying shape and profile combinations.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As previously described, and with further reference to the attached illustrations, the present invention discloses a variety of no snap-action rivet configurations and associated non-slide actuated molding process, such for avoiding the necessity of forming an undercut profile in the molded rivet stem. As will be further described, each of the variants incorporates a partially hollowed rivet stem (solid at the outermost end but hollowed from at least the intermediate interior and typically through the central opening at the flattened top) which is formed in combination with an opposing and through-seating aperture, the latter typically including any narrowing or angling of the material rim surrounding the aperture such including any of an angled/chamfered or saucer-like profile which terminates in a thin/sharpened inner rim edge and which defines a diameter of somewhat lesser dimension than that presented by the cross section of the inserting rivet stem. For purposes of the present description, the narrowing of the aperture defining rim edge will be referenced hereinafter as being “chamfered” it being understood that this term can be extended to cover a multitude of different narrowing profiles not limited to any straight angle or saucer-like configuration.

In this fashion, and upon press-fitting the solid end-most portion (tip) of the rivet stem through the aperture and in resistive contact with the narrowed rim edge, the intermediate extending walls of the stem defined by the hollow interior are caused to deflect or bow inwardly to thereby create the equivalent of the desirable (and withdrawal resistant) undercut. As will also be described, an associated forming process also disclosed for injection molding the rivet and dispenses with the need of providing for movable slide actuation of the undercut forming portions (e.g. providing a no-action mold). Other applications of the article and associated forming process include replacing sonic welds, push pins or traditional latching features. Post and hole configurations of any article produced according to the present inventions can vary from circular as shown, it further being understood that the post and hole can additionally vary from one another in use.

Referring first to FIG. 1 and related FIG. 5B, an illustration is generally provided at 10 in cutaway of a selected no-action snap rivet feature forming a fastener engaging portion according to one non-limiting embodiment of the present inventions. For purposes of the present description, the fastener portions can include any type of injection molded plastic, such typically including a combination of rigidity and structural collapsibility which is associated with the integral construction of the upper and lower mounting portions of the supporting structure or housing components with which the fastener portions are formed.

As previously indicated, the engaging fastener portion (also termed hereinafter to include an upper mounting portion) has an upper surface 12 which is understood to include any of an individual enlarged fastener head, or which can be integrated in singular or plural fashion within a first mounting surface (see also underside of upper engaging component in FIG. 7). A partially hollowed rivet stem extends from an underside surface 14 of the fastener head or first mounting layer, such defining a thickness between the upper 12 and lower 14 surfaces.

As further depicted in related FIGS. 4 and 5A-5B, the stem (at 16) is hollowed, further at 18, between at least an intermediate interior end wall 19 communicating with a solid outermost end 20 to an open rim edge 21 communicating with the upper surface 12 of the rivet/fastener head. The present invention contemplates the hollowed or cavity interior of the stem extending either partially or completely from the lower/interior end wall 19 to the upper rim edge 21. In combination, an opposing and through-seating aperture is provided in a base mounting surface 22, such depicted as a rectangular or square shaped portion however again being understood to include any secondary mounting surface for receiving the inserted stern 16 and which can also be any larger sized surface (referencing again FIG. 7) incorporating a plurality of mounting locations which match a number and arrangement of stems 16 and for resistively anchoring the surfaces together in the manner described herein.

The mounting surface 22 (hereinafter referred to as a lower receiving portion) further exhibits, in one non-limiting embodiment, an angled or saucered/chamfered profile, at 24, which terminates in a thinner/sharpened inner rim edge 26. As shown, the rim edge defining the inner aperture defines a diameter of somewhat lesser dimension than that presented by a cross section of an exterior annular surface associated with the inserting rivet stem.

The variances in this force-fitting inter-dimensional relationship are based on a number of considerations, not limited to the material construction of the inter-engaging rivet fastener portion 12 and aperture receiving location 22, the thickness of the outer perimeter wall associated with the stem 16, as well as the thinned rim edge configuration 26 formed in the receiving layer 22. In this fashion, and upon press-fitting the solid end-most portion 20 (tip) of the rivet stem 16 through the aperture in resistive contact with the narrowed rim edge 26, and then beyond the thinned edge 26, the subsequent alignment of intermediate extending walls of the stem defined by the hollow interior aligning with the thinned edge 26 cause the annular stem wall to deflect or bow inwardly (see concave or collapsing profile at 28) to thereby create the equivalent of the desirable (and withdrawal resistant) undercut in the rivet stern.

Referring to FIGS. 2A-2C, presented are a series of views of an undercut snap action fastener according to the Prior Art and which provide a contrast to the (no-action) snap fasteners of the present invention. Specifically,the typical molded fastener exhibits a first mounting (upper) layer 30 with which is formed an engagement body 32 (shown having a generally elliptical or non-liner shape) and which also includes a further undercut region, see at 34, typically proximate to an underside of the layer 30. A second mounting layer, at 36, likewise includes an aperture defined by an inner edge 38 (typically non-chamfered) and, upon downwardly engaging the first/upper layer 30 through the aperture in the second/lower layer 36 of the fastener, the body 32 is caused to resistively fit through the rim edge 38 until fully seating at the uppermost/inner undercut profile or region 34.

FIGS. 3A-3C present a series of process views of a simplified depiction of a mold assembly, at 40, with inter-movable slides 42/44 for producing the snap action fastener 30 according to the Prior Art. For purposes of ease of illustration, only a single half of the injection molding tool is depicted, with other necessary and known components for producing the molded part not being illustrated.

FIG. 3A depicts a first stage in which the fastener part 30 is initially formed (with the slides inwardly positioned relative one another). FIG. 3B subsequently shows the slides 42/44 movably retracted away from one another, such motion being generally referenced as “action” of the tooling and which is required in order to both form the undercut region 30 as well as to permit subsequent removal of the part from the tool (FIG. 3C). As therefore illustrated, the formation of the undercut in the fastener upper part adds complexity to the injection mold tool and requires the inclusion of the inter-displaceable die slides 42/44 in order to facilitate part removal at the end of the injection molding process.

As previously described, FIG. 4 is an exploded view of the no-action snap fastener, such as according to the previously described embodiment 12 and in which (unlike the prior art views of FIGS. 2-3) the underside extending stem 16 of the upper fastener portion exhibits no undercut features which would require action on the tooling (e.g. the incorporation of die slides or the like). FIG. 5A depicts a combination exploded and cutaway of the engaging rivet 12 and receiving surface 22 with a dovetailed and narrowed/thinned profile for receiving the stem in the manner described with respect to FIG. 1. As again shown in FIG. 5B, the thinned sidewalk of the stem exhibited by the hollowed interior 18 of the feature result in inward collapse (again at 28) once the solid tip 20 of the stem is forced through the smaller dimensioned opening established by the rim edge 26.

FIGS. 6A-6B correspond to FIGS. 3A-3C and illustrate a process view of a mold assembly, a first or lower half of which is representatively shown at 46 for producing the upper fastener 12 and again not requiring movable slides for producing the fastener of FIG. 4. In this manner, the molded part 12 can be directly removed from the tooling without the requirement of any die slide or other action for accommodating any integrally formed undercuts.

Proceeding to FIGS. 7, 8 and 9A-9B a series of exploded views are illustrated generally at 48, 50 and 52, respectively, of a collection of alternate applications of the no-action snap fastener and which can be utilized to replace such as sonic welds, push pins or traditional latching features. The construction of the extending stem portions, respectively show at 54, 56 and 58 in each of FIGS. 7, 8 and 9A, are similar to as shown in FIGS. 1, 4 & 5A-5B and so that they each provide for a controlled inward collapse, as specifically illustrated in FIG. 5B, once forced through inner rim edge profiles (at 60, 62, and 64 respectively) defined in variously configured lower mounting surfaces 66 (generally flattened lower layer with rim edge as in FIG. 7), 68 (generally planar shaped lower layer as in FIGS. 8) and 70 (generally three dimensional structural article or box shape as in FIG. 9A). The configuration of the inner rim edge configured apertures in each of these figures is similar to that previously described in reference to the receiving surface 22 of FIG. 1 with narrowed rim edge profile (again depicted as dovetail or saucer-like surface 24 terminating in inner thinned/narrowed edge 26)

As previously described, the no-action snap fastener design focuses on the inter-fitting and controlled collapsing arrangement established between the hollow interior intermediate portion of the stem and the inner rim edge profile of the associated mounting aperture. The embodiments 48, 50 and 52 depicted can, as previously disclosed, exhibit any type of shape or configuration.

In the case of the variant 48 (FIG. 7), a two piece assembleable tray includes a rectangular and interiorly open upper body 72, from a bottom perimeter rim surface of which project the various mounting stems 54. In the instance of the variant 50 (FIG. 8), an “L” bracket 74 having a lower side with an aperture 76 formed therethrough is provided and such that the stem 56 of the associated upper fastener is inserted through the aperture 76 and aligning underneath positioned aperture 62, and in order to mount the bracket 74 to the plate shaped member 68.

In the still further example of the variant 52, a lid 78 is pivotally mounted to an upper edge of the lower three dimensional box shape 70, such as along edge 80 which can constitute a hinge. Upon pivoting the lid 78 over the top rim edge of the box 70, a forward projecting portion 82 of the lid, this including a downwardly pivoting hinge edge (arrow 84) facilitates the underside projecting stern 58 to collapse-ably engage through the aperture 64 in order to seal the enclosure as depicted in FIG. 9B. The varying examples shown are intended to provide non-limiting examples of the limitless range of potential applications for the collapsible fastener design in use with any engagement stem (whether or not associated with a separate fastener or rivet) and receiving location, again including the dovetail and inner/narrowed edge profile for defining a dimensioned aperture for receiving the stem in a friction inserting fashion as described above.

FIG. 10 is an assembled cutaway in perspective, generally at 86, of a variant of the no-action snap fastener utilizing a non-chamfered configuration (see annular or flat rim edge 88) in the mounting surface hole in combination with a more elongated and interiorly hollowed stern 90, this in comparison to that shown in the variant of FIG. 1. Similar to the previously described variant, the upper fastener 92 exhibits a hollow interior (see inner rim wall 94) which communicates through the stem 90, the interior terminating at an end wall 95 from which extends a solid end-most portion 96 of the stern.

In this fashion, the passage of the solid portion 96 through the bottom (in this instance non-chamfered portion) surface and adjoining edge of lower fastener portion 98 is such that the rim edge is flat and, following through-inserting of the solid end-most portion 96, results in controlled collapse (see at 90) of the hollowed interior portion of the stem. As further shown, the elongated aspect of the stem 90 (as compared to that at 16 in FIG. 1) facilitates use with a non-chamfered or narrowed rim edge 88 (as compared to at 26) for providing adequate inter-engagement.

FIGS. 11A-11B illustrate another embodiment, generally at 100, related to that of FIG. 1 and illustrating a polygonal (non-circular cross sectional shaped) configuration associated with the underside projecting stem, at 102, of an upper fastener 104, such further including a hex profile aperture (see as further depicted by upper edge 106) extending to an end surface 108 terminating in a solid end 110 of the stem 102. As further shown, the lower fastener mounting surface, at 112, exhibits a mating inner narrowed perimeter edge configuration, in the form of a narrowed hex shaped rim defined aperture 114, associated with the dovetail configuration in the base mounting layer 112, this providing one non-limiting example of a non-round cross sectional shaped stem which engages with a likewise cross sectional shaped rim defined aperture according to the aspects of the present invention.

FIGS. 12-14 illustrates a further collection of exploded views of alternate no-action snap fasteners, see respectively at 116, 118 and 120, exhibiting varying shape and profile combinations. In the case of FIG. 12, this includes upper fastener 122 with downwardly projecting stem 124 (with central extending and interiorly hollowed aperture 125) engaging a lower receiving location 126 having a non-matching cross sectional rim edge aperture profile 128. In the instance of FIG. 13, upper fastener 130 includes a lower projecting stem 132 which is internally communicated by an inner hex aperture profile 134, such that an outer hex profile of the stem 132 can engage through a non-matching mounting aperture in the lower receiving location 136 (this further shown by circular dovetail profile 138 with narrowed circular rim edge 140).

FIG. 14 further depicts upper fastener 142 having lower extending stem 144, an interiorly extending aperture 145 defined within the outer hex profile of the stem 144. The lower fastener, at 146, replicates that shown at 136 in FIG. 13 with a dovetail inner profile 148 in the lower receiving layer (or receiving fastener) 146 terminating in a circular narrowed rim edge 150. The example of FIG. 14 exhibits the ability of non-matching cross sectional profiles between the upper fastener stem and the lower fastener aperture rim, such still permitting secure engagement. In this fashion, any mating or non-mating configuration between upper fastener stem and lower fastener rim aperture can be accommodated, so long as the hollowed intermediate extending interior of the stem facilitates pre-passage of the solid end-most portion of a larger dimensioned stern (relative to the inner rim edge defined diameter of the receiving location), following which translation of the hollowed intermediate portion of the stem is caused to inwardly collapse in order to permanently affix the fasteners together.

Having described my invention, other and additional preferred embodiments will become apparent to those skilled in the art to which it pertains, and without deviating from scope of the appended claims. 

I claim:
 1. A fastener assembly, comprising: an engaging portion having a projecting stem which is interiorly hollowed over at least an intermediate extending range, said stem including a solid end most extending portion; and a receiving portion having a surface, within which is configured an inner rim defined edge, a diameter of an aperture between said rim edge being less than a diameter of an inserting portion of said stem so that, upon pre-passage of said solid most extending portion, an intermediate hollowed interior portion exhibiting a controlled collapse against said rim edge.
 2. The assembly as described in claim 1, said stern having a circular exterior cross sectional profile.
 3. The assembly as described in claim 1, said stem having a polygonal exterior cross sectional profile.
 4. The assembly as described in claim 1, said inner rim defined edge further comprising a chamfered shape terminating in a narrowed rim profile.
 5. The assembly as described in claim 1, said inner rim defined edge further comprising an annular inner profile equal in dimension to that of said receiving portion.
 6. The assembly as described in claim 1, further comprising said exterior cross sectional profile of said stem and said inner rim defined edge defining matching profiles.
 7. The assembly as described in claim 1, further comprising said exterior cross sectional profile of said stem and said inner rim defined edge defining varying profiles.
 8. The assembly as described in claim 1, further comprising said upper and lower engaging portions exhibiting any dimensional shape,
 9. The assembly as described in claim 8, said upper and lower engaging portions further collectively comprising an open or enclosing three dimensional housing.
 10. A fastener assembly, comprising: an engaging portion having a projecting stem which is interiorly hollowed between an upper edge and a solid end most extending portion; a receiving portion having a surface within which is configured an inner rim edge; and a diameter of an aperture defined by said rim edge being less than a diameter of an inserting portion of said stem so that, upon pre-passage of said solid most extending portion, an intermediate hollowed interior portion exhibiting a controlled collapse against said rim edge to affix said engaging portion to said receiving portion.
 11. The fastener assembly as described in claim 10, said engaging portions each further comprising a rivet with an annular enlarge head in communication with said stem.
 12. The fastener assembly as described in claim 10, further comprising said engaging and receiving portions being integrated into first and second locations of a three dimensional structural article.
 13. The fastener assembly as described in claim 10, said stem having a circular exterior cross sectional profile.
 14. The fastener assembly as described in claim 10, said stem having a polygonal exterior cross sectional profile.
 15. The fastener assembly as described in claim 10, said inner rim edge further comprising a chamfered shape terminating in a narrowed rim profile.
 16. The fastener assembly as described in claim 10, said inner rim edge further comprising an annular inner profile equal in dimension to that of said receiving portion,
 17. The fastener assembly as described in claim 10, further comprising said exterior cross sectional profile of said stein and said inner rim edge defining matching profiles.
 18. The fastener assembly as described in claim 10, further comprising said exterior cross sectional profile of said stem and said inner rim edge defining varying profiles.
 19. The fastener assembly as described in claim 10, further comprising said upper and lower engaging portions exhibiting any dimensional shape.
 20. A fastener assembly, comprising: an engaging portion having a projecting stem which is interiorly hollowed between and upper edge and a solid end most extending portion; a receiving portion having a surface within which is configured an inner rim edge, said inner rim edge further having a chamfered shape terminating in a narrowed rim profile; and a diameter of an aperture defined by said rim edge being less than a diameter of an inserting portion of said stem so that, upon pre-passage of said solid most extending portion, an intermediate hollowed interior portion exhibiting a controlled collapse against said rim edge to affix said engaging portion to said receiving portion. 